Cross thread laying mechanism for sewing machines



April 26, 1932. MOFFATT 1,855,254

CROSS THREAD LAYING MECHANISM FOR SEWING MACHINES Filed July 19, 1928 5 Sheets-Sheet l April 26,1932. J R, MQFFATT 1,855,254

CROSS THREAD LAYING MECHANISM FOR SEWING MACHINES Filed July 19, 1928 5 Sheets-Sheet 2 iign.v :2

Z] K 9 rl| N 34' J2 I II] lllul L9] I v MIMI/f! f) n; 21 J6 I I i 1 a" 0 5 (I April 1932- J. R MOFFATT 5 CROSS THREAD LAYING MECHANISM FOR SEWING MACHINES Filed July 19, 1928 5 Sheets-Sheet 3 April 26,1932. MOFFATT 1,855,254

CROSS THREAD LAYING MECHANISM FOR SEWING MACHINES Filed July 19, 1928 5 Sheets-Sheet 4 April 26, 1932. J. R. MOFFATT 1,855,254

CROSS THREAD LAYING MECHANISM FOR SEWING MACHINES Filed July 19,-1928 5 Sheets-Sheet 5 i I l Patented Apr. 26, 1932 UNITED STATES PATENT OFFICE JAMES R. MOFFATT, OF CHICAGO, ILLINOIS, ASSIGNOR TO UNION SPECIAL MACHINE COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS CROSS THREAD LAYING MECHANISM FOR SEWING MACHINES Application filed July 19, 1928. Serial No. 294,009.

The invention relates to new and useful improvements in sewing machines, and more particularly to a cross thread laying mechanism used in conjunction with a covering stitch forming mechanism.

An object of the invention is to provide a cross thread laying mechanism which includes a cross thread guide and a device cooperating therewith to form a loop in the cross thread with means for supporting and actuating said cross thread guide and loop forming device from a. single rocking arm.

A further object of the invention is to provide a cross thread laying mechanism of the above type wherein the cross thread guide moves back and forth in a line substantially parallel with the line of feed at one side of the needles and the loop forming device has a notched end movable in a curved path in front of the needles from a point at one side of the needles to a point at the other side thereof.

A further object of the invention is to provide a cross thread laying mechanism having a thread controlling means whereby the cross thread is pulled from the su ply to provide thread for the forming of t e loop as the loop forming device moves into engagement with the cross thread.

A still further object of the invention is to provide a cross thread laying mechanism of the above type wherein the thread c0ntrolling means takes up the slack in the cross thread and places said thread under tension as'the cross thread loop is completed so as to insure the proper positioning of the cross thread relative to the needles.

Another object of the invention is to provide a cross thread laying mechanism of the above type wherein the cross thread is taken up after the completion of the cross thread loop for drawing the cross thread loop taut.

These and other objects will in part be obvious and will in part be hereinafter more fully disclosed.

In the drawings which show by way of illustration one embodiment of the invention:

Fig. 1 is a front view of a part of a machine embodying the improvements.

Fig. 2 is a rear view of a portion of the machine.

Fig. 3 is an end view of a portion of the machine.

Fig. 4 is a View partly in section and partly in plan showing the cross thread guide, the devices for forming a loop in the cross thread, and means for supporting and actuating the same with the parts in position for completing the cross thread loop.

Fig. 5 is a similar view but showing the parts positioned for the loop forming device to engage the cross thread.

Fig. 6 is a front view showing more or less diagrammatically the needles the cross thread guide, and the hook end of the loop forming device, and showing the position of the strand of the cross thread loop running to the cross thread guide.

Fig. 7 is an enlarged diagrammatic view showing the needle threads and the cross 1ghread formed into loops and locked there- Fig. 8 is a view showing the thread controlling means for the cross thread in side elevation with the needle bar at the upper end of its stroke.

Fig. 9 is a similar view but showing in full lines the needle bar at the lower end of its stroke and in broken lines the cross thread controlling element as having completed its Bake-up action on the up stroke of the needle Fig. 10 is a detail in plan showing the cross thread controlling means.

The invention is directed to a cross thread laying mechanism for sewing machines used in conjunction with a covering stitch forming mechanism. The machine is preferably provided with three needles and a single co-operating looper beneath the work support which is of the usual construction. The cross thread which is laid on top of the material and secured by the needle threads is led from a supply through suitable tension to a cross thread guide. Associated with this cross thread guide is an oscillating member having a notched end which is adapted to engage the cross thread as the member oscillates for forming a loop in the cross thread. This loop is preferably laid so that it is entered by the two needles farthest disposed from the cross thread guide, while the other needle passes outside of the cross thread loop and secures the cross thread by laying its needle thread over the shank of the cross thread loop.

The invention is directed particularly to the manner of mounting and operating the cross thread guide and loop forming device. The member for forming the loop in the cross thread is carried by an arm pivotally suported for horizontal movement. The arm 1s supported by a sleeve member which is formed with a second arm through which the sleeve is oscillated and this imparts oscillations to the loop forming member. The cross thread guide is carried by an L-shaped arm which is pivotally secured to the second arm on the sleeve for imparting oscillations thereto. An oscillating shaft is provided with an arm which is attached to this L- shaped arm at the elbow. The centers of these arms are so disposed that when this shaft is oscillated it will impart oscillations to the arm carried thereby and this will impart oscillations to the sleeve and the oscillating member carried thereby. It will also impart a movement to the cross thread guide which is substantially parallel with the line of feed and disposed at one side of the needles.

Associated with this cross thread laying mechanism is a cross thread controlling means carried by the needle bar and movable up and down therewith. This cross thread laying means is in the form of a cam shaped plate which is so disposed relative to the stationary guides as to move into engagement with the cross thread and pull the cross thread from the supply on the up stroke of the needles. This drawing on the cross thread occurs at the time when the loop forming device moves into engagement with the cross thread. The controlling member for the cross thread is also provided with another cam portion which engages the; cross thread and places the same under tension at the time when the cross thread loop is completed and this insures that the strands of the cross thread loop will be taut and properly positioned relative to the needles. On the down stroke of the needle bar this cam plate again engages the cross thread and takes up the slack therein. This occurs after the cross thread loop is formed and draws the cross thread loop comparatively taut.

Referring more in detail to the drawings, the invention is shown as applied to a sewing machine having the usual form of work support 1 and overhanging arm 2, which carries a needle bar 3 provided, as shown in the drawings, with three needles, 4, 5, and 6. Cooperating with these needles beneath the work support is the ordinary thread carrying looper which has not been shown. The needle bar is reciprocated by means of a needle lever 7 connected by a link 8 to the needle bar. The needle threads are indicated at n in the drawings. This three-needle stitch forming mechanism is of the well known type and further disclosure thereof is not thought necessary. The machine is especially adapted for forming a covering stitch. The needle threads on the upper face of the fabric are joined by a cross thread which is laid into a loop. The cross thread is indicated at c in the drawings. This cross thread passes from the supply through a suitable thread guide 9 and thence to an eye 10 in a member 11 se cured to the overhanging arm. This member 11 is stationary. As clearly shown in Fig. 10 of the drawings the member 11 is provided with a U-shaped portion 12. Opposit-e the thread eye 10 is a second thread eye 13. The cross thread 0 passes first through the eye 10 and then the eye 13. This cross thread is then led to a movable cross thread guide 14. Said cross thread guide is provided with an eye 15 back from the end thereof and an eye 16 at the end thereof. The cross thread guide 14, as clearly shown in Figs. 4 and 5, is carried by an arm 17 which is L-shaped. This arm is pivotally mounted at 18 on a projecting arm 19 carried by a sleeve 20 which is mounted for free oscillation in a horizontal plane about the guide bar 21 which is associated with the presser bar 22. Mounted on the lower end of the presser bar 22 is a presser foot 23 and cooperating with this presser foot is a feeding mechanism which includes a feed dog 24.

The sleeve 20 is provided with a projecting arm 25. This projecting arm 25 carries a member 26 having a notched end 27. This notch faces outwardly and engages the cross thread running through the cross thread guide for forming a loop therein. The loop forming member 26, as noted, is carried by the arm 25 and when this arm is oscillated, the notched end of the loop forming member will move in a curved path about the axis of the guide bar 21 as a center. This curved path lies in front of the needles and extends from a point at one side of the needles to a point at the other side thereof, as clearly shown in Figs. 4 and 5. Mounted on the overhanging arm is a shaft 28. This shaft 28 is arranged with its axis vertical. The shaft carries an arm 29 and the arm 29 is pivoted at 30 to the elbow of the arm 17. This shaft 28 is oscillated by means of a link 31 which, in turn, is connected to an arm 32 carried by a horizontal cross shaft 33. This cross shaft 33 carries an arm 34 with which an eccentric strap 35 cooperates. The eccentric strap is actuated by an eccentric on the main shaft beneath the work support.

In Fig. 5 of the drawings the thread guide is shown at the forward end of its stroke and the loop forming member about to engage the cross thread. WVhen the arm 29 is oscillated said arm and the portion of the L-shaped member 17 between the pivotal point 30 and the pivotal point 18 will move toward alignment as clearly shown in Fig. 4. As these arms move nearer alignment it will force the arm 19 to the left and cause the sleeve 20 to turn in a clockwise direction about the center of the guide bar 21. This imparts a movement to the member 26 which carries the hook end thereof into engagement with the cross thread and forms in the cross thread a loop as clearly shown in Fig. 4;. During this formation of the cross thread loop the cross thread guide is moving toward the rear of the machine. The end of the arm 17 will move rearwardly in a curved path about the center of the guide bar 21. The pivotal connection 30 between the arm 29 and the arm 17 willalso move rearwardly in a curved path about the axis of the shaft 28 as a center. This combined rearward movement of the pivotal point 18 and the pivotal point 30 in the arm 17 brings about a substantially right line movement in the eye 16 at the end of the cross thread guide member which is parallel with the line of feed and at one side of the needles. This positions the thread eye 16 slightly in rear of a line passing through the ghrge needles at right angles to the line of The strand of the cross thread loop running from the hook end of the oscillating member 26 to the eye 16 will be laid, therefore, in front of-the two left hand needles as viewed in Fig. 4 and in rear of the right hand needle. The needles are preferably set with their points at different levels as shown in Fig. 1. This strand of the cross thread is laid against the front face of the middle needle and carried past the right hand needle beneath the point thereof which is set higher so that the middle needle will, in a measure, aid in the proper positioning of this strand of the cross thread loop. The other strand of the cross thread loop, of course, runs from the hook end of the oscillating member 26 to the previously formed stitches. As clearly shown in Fig. 7 the cross thread is formed into a series of loops. The strand 0 is the one running between the hook end of the oscillating member 26 and the eye 16 of the cross thread guide. The strand 0 is the strand running from the hook end of the member 16 to the previous stitch.

The needle thread loops of the needle 4 are indicated at n; the needle thread loops of the needle are indicated at M; and the needle thread loops of the needle 6 are indicated at 11. and the fabric is indicated at F.

From the above it will be apparent that a cover thread laying mechanism has been provided wherein the co-operating cross thread guide member and the loop forming device are both operated from a single arm and a right line movementjmparted to the cross thread guide, while a curved path of movement is imparted to the loop forming member which extends substantially at right angles to the path of movement of the cross thread guide. The mechanism is very simple and easily operated, and may also be actuated at a very high speed. Both the cross thread guide and the loop forming member are adjustably mounted on their supporting arms so that they can be shifted to different set positions and thus properly set relative to the needles for cooperation with each other and for the proper placing of the formed cross thread loop.

Associated with this cross thread laying mechanism is a cross thread controlling means for controlling the cross thread. As noted above, the cross thread passes from the supply through the thread eyes and 13. Mounted on the needle bar is a cam plate 36. This cam plate is located for movement between the eyes 10 and 13 through which the cross thread passes. The cam plate is provided with a laterally projecting arm 37 which is secured to the needle bar by screws so that the arm is rigidly attached to the needle bar and moves up and down with the needle bar. This cam plate has an inclined face 38 which inclines downwardly and outwardly away from the needle bar to a rounded shoulder 39. It then inclines toward the needle bar as indicated at 10, and terminates in a hook shaped cam portion 41. hen the parts are positioned as shown in Fig. 9 the needles are at the lower end of their stroke and the device for forming a loop in the cross thread is at the rear end of its stroke as shown in Fig. 5.

As the needle bar moves up the loop forming device engages the cross thread and begins the formation of the cross thread loop. The inclined face 38 of the cam plate engages the cross thread passing from the eye 10 to the eye 13 and deflects said cross thread, drawing thereon as indicated in the broken lines in Fig. 9. The cross thread at this time is taut and the cross thread is drawn from the supply. As the cam plate continues its upward movement the cross thread passes over the rounded shoulder 39 and is released and gradually given up to the hook forming device as it moves on to form the cross thread loop. lVhen the needle bar reaches the upper end of its stroke the loop forming device has reached the end of its forward stroke and is positioned as shown in Fig. 1. At this time the cross thread loop has been fully formed and properly positioned for the needles to pass the strands in the cross thread loop. The cam portion 41 of the cam plates 36 now engages the cross thread and takes the slack out of the cross thread, thus holding the cross thread taut at the time when the needles are passing the strand 0' in the cross thread. This insures that the right hand needle will pass in front of the strand while the other two needles will pass in rear of this strand. On the down stroke of the needle bar the inclined face 40 of the cam plate will engage the cross thread passing between the eyes 10 and 13 and will draw on the'cross thread, thus taking up the slack in the cross thread formed by the loop forming device releasing the loop and this will draw the cross threadloop substantially taut around the needles, and insures that in the completed stitch formation the cross thread loops will be substantially taut within the needle threads.

This cross thread controlling means is of particular advantage in connection with the cross thread laying mechanism described, wherein the cross thread loop is formed by a single loop forming device as the thread is drawn from the supply to enable the loop forming device to form its loop without undue strain upon the cross thread. It also insures that the cross thread will be taut at the time that this loop forming device and the cross thread guide cooperating therewith are positioning the strand of the loop in a certain desired relation to the path of the needles, and it is of further advantage in the drawing of the cross thread loop taut when released by this loop forming device which has a relatively long movement in the forming of the cross thread loop.

It is obvious that minor changes in the details of construction and the arrangement of the parts may be made without departing from the spirit of the invention as set forth in the appended claims.

Reference is made to applicants co-pending application Serial No. 452,683, filed'May 15, 1930, which latter case discloses and claims certain subject matter herein-disclosed but not claimed.

Having fully described my invention, what I claim as new and desire to secure by Letters Patent is 1. The combination of a plurality of needles and a cross thread laying mechanism therefor, including across thread guide, a cross thread loop forming device oscillating in a curved path in front of the needles, a pivotally supported sleeve member, an arm extending from said sleeve member and carrying said loop forming device, an L-shaped arm carrying said cross thread guide and having the end opposite the cross thread guide pivotally mounted on an arm projecting from said sleeve member, an oscillating shaft, an arm carried thereby and connected to the cross thread guide at the elbow therein, said shaft and said sleeve member being positioned so that the cross thread guide is moved back and forth in a path at one side of the needles and substantially parallel with the line of feed.

2. The combination of a plurality of nee dles, a cross thread laying mechanism therefor, including a cross thread guide, a. cross thread loop forming device oscillating in a curved path in front of the needles and having a notched end for engaging the cross thread and forming a loop therein for the needle farthest from the cross thread guide to enter, devices for supporting said loop forming device, a member connected to said supporting means for the loop forming device and carrying said cross thread guide, said member being L-shaped, an oscillating shaft, an arm carried thereby and connected to said member at the elbow for imparting movements thereto and to said support for the loop forming device.

3. The combination of a plurality of needles and a cross thread laying mechanism therefor, including a cross thread guide, a cross thread loop forming device, a member pivotally mounted in rear of the needles and carrying said cross thread loop forming device, an actuating shaft, an arm carried thereby, and a member pivotally connected to said arm and to the member carrying the cross thread loop forming device for supporting the cross thread guide, said connections being disposed so that the cross thread guide is moved back and forth substantially in a line at one side of the needle.

4. The combination of a plurality of needles and a cross thread laying mechanism therefor, including a loop forming member mounted for oscillation about an axis located in rear of the stitching point, a thread guiding member pivotally connected to said loop forming member, devices connected to said thread guiding member for imparting back and forth movements thereto and oscillating movements to the loop forming member, the relative paths of movement of the connecting points between the thread guiding member and the loop forming member and between the thread guiding member and the actuating devices being so disposed that the thread guiding member will be moved in a line substantially parallel to the line of feed.

In testimony whereof, I afiix my signature.

JAMES R. MOFFATT. 

